With advance of technology now automatic cleaning apparatus capable of providing automatic dust suction function has been developed and marketed. It no longer needs people to drag and control the position of dust suction port to do suction of dust. It can move by itself and automatically perform dust suction at the same time to substitute manpower to do cleaning task. Once the automatic cleaning apparatus is started by users it can automatically perform dust suction action in a space where cleaning is intended. This greatly increases the convenience of the users in doing the cleaning task. In addition, after the automatic cleaning apparatus has performed automatic dust suction operation for a period of time it can automatically return to a charging station for charging before the power is depleted.
For instance, Taiwan patent No. M453295 discloses an automatic guiding charging apparatus for robotic cleaning machines. It includes a charging dock that requires at least three signal emission lamps, with swerved moving signal emission lamps at two sides to form an inverse V shape. However, the inverse V-shaped angle requires precise adjustment. Too small of the angle could cause signal overlap and result in the cleaning machine unable to enter the charging dock location. Too big of the angle makes entering the charging dock location inaccurate and difficult. Moreover, the cleaning machine has only one receiver at the front end that has a limited receiving angle, generally less than 120 degrees. As a result, when the cleaning machine moves in a direction slightly outwards at a small angle it cannot capture the signal emitted from the charging dock, and moves away from the charging dock without getting normal charge. Moreover, the cleaning machine also has metal electrode plates at the front end for charging. In the event that the cleaning machine bumps against furniture or other articles the metal electrode plates could be easily contaminated and result in poor contact for charging.